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Pi and the Area of Circles


Date: 05/11/97 at 01:11:33
From: Jason Textor
Subject: Pi in the area of circles

If pi truly goes on and on forever without repeating, is it impossible 
to find the EXACT area of a circle?


Date: 05/11/97 at 03:09:45
From: Doctor Mike
Subject: Re: Pi in the area of circles

Jason,
  
Sort of. When you use the A = pi*R^2 formula you are representing the 
exact answer in terms of pi, which can be determined to whatever 
accuracy you need. Fortunately you rarely really need more than 
several dozen places, even in the space program. Besides, if you knew 
pi to a "gazillion" places, and could find the area to a "gazillion" 
places, where could you write down the answer? Or where could you find 
a person with the patience, or life-span, to listen to the answer?  
   
Here's another thing to think about. Let's say the radius of the
circle in question is exactly "2 over the square root of pi" feet,
which is *about* 13 and a half inches. Here it is impossible to find 
the exact value of the radius, but the area is exactly 4.
  
I hope this helps.
  
-Doctor Mike,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/   
    
Associated Topics:
Middle School Conic Sections/Circles
Middle School Geometry
Middle School Pi

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